SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7039327818fbb7696932daac6f8826fef0fb9db6a1ecc2bfe1a04a3382f071bf' 
  AND token = 'beObHkJIraMjXYykfSvQePAKF2mptBofL7r+0Ce+wYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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