SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12aa8c20dadcb412b560e6c95d5a7b88878ec952dbb25fa7fa96f59c1e08450a' 
  AND token = 'mkS1YOMt05WeBlzelMPbP37FNomXdNP/SF4Qz8q2SNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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