SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea7b447ce80e6940011ea5e256c974225e0566fcccc892ffc83afa55ebf8f275' 
  AND token = 'ZpeW02NpnPQeQC5BCupfMmn4/PdhYALVUOR52XTFMlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00124

JSON explain

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