SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '517ecc4a853a07b90eff71b54d3566e4d44279942bc1922576918cc5dcdb6b95' 
  AND token = 'R+p5u6zyUPv9fqOLFs7kUhRgLIhofYT+U1NLhXBomz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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