SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93369a6f4c67703455d4d1c146fb52c9196833ef1fc39f603e72a2f7088b5643' 
  AND token = 'EIKX+Yrg3Os/RnRbsqpcZFpRBNIYukndUp/Vlu/azr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}