SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81db1a5d758f4be47749b9ea91282e8cd374fa94e44cc6377f7ab331a1265735' 
  AND token = 'suUQ3CmSjKfzPZHlztC5EKtrHHx4+cWfxfPXZ1cLGVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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