SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2d052894cb621fe1b6c91fa6405cd68a11c275b89975ccf967c6d357aa6ff6' 
  AND token = 'doxpE/6hhs85WhO5SyIvoAgkZ6AJrS3BJO6ENxFnYPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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