SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3384620720ebc563ab7c226ec1d30a30ebf1f9994c4ac0f9cb8381eedad361f' 
  AND token = 'T4tYFLs2Swi/OB7qevoPesVo0L7rhI/ZjE5+HLzJrN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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