SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e19fd129f71319c2f195e41ec195aac02d43f4984e98fc2a33b05e6c13d7ea93' 
  AND token = 'TttP2qvNvLuDVjg7/DXjK/WdPGi4SY3CUBObnHhl4wY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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