SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eed6b448c4cff880e4615ba115da61bc2abd5b3e25a67f2e3dca558e1474bcd' 
  AND token = 'bLDkHGFHbe+4DCu2r3RQ8Jdq7PG5lxNlCAbO97ql3xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}