SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49a395af00d976ece1b9340ab665ca2bcf7a102b26fab942fdb1bf516c1de4c' 
  AND token = 'YvbfvXLD4At4UaBSKZ5ehby8zz8fdjbmotFLXZciCQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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