SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c841619cf260747f0499d5e538f8cedb420ce46b88d8f064f5594ecd7359c67c' 
  AND token = 'VS60GY8RkDQBLATXYaqxC+LymXVRswwWnpCd6IdrLJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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