SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'abe808bccf71132b7a88b59eddce89c3e819a0e77519ad9c730c5d9606d45564' 
  AND token = 'lxQ5g/XHs+kP5dZ7Msz3c65sZW4jthh0zIsbxZ7cABk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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