SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd50c27abb641684b6144f0864fca0523316abab5610fb25965f66930d167182f' 
  AND token = 'V23c6egebIoqpwghGVKBfBFY3N1xWJBtjtREiUVSmk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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