SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c73f53d4087c0b4d9fe0c689a38f9c42a9f61c6da66567f6cfbe2dd104b720f' 
  AND token = 'yyM+1GibOOoTR1s0sbCCGth+z4X1/+1qSJi/7av62xQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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