SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd20345aa9c25585a42bc550bee5ea122c83d44c04ec549824e10a028477004a8' 
  AND token = 'jtunyCJ6rZZBHttqXIwvVL/csPfSPwTT/FSW7YBtQdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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