SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b00f47a45e6a1bd8eaac41e184280e9daf552a863b82b3867ca4cbb5048595' 
  AND token = 'Gb28KeyLkABr6H2ZXSC7gNcas6WqbRUkgyKgPN0fFnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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