SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '940fc3650700f6c6a721b0fb40ce2a8224625714efb8c374f17afd94dce26b44' 
  AND token = 'I+MQWvu51K//zsC8Vib5rUoTm1U9YdW7Wge9iL5VK+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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