SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8140ab2e950762f39b2fbbee998d55da7c00181e8a960dd9f5278b5667275cc' 
  AND token = 'U0Yxv9iC61bcjMw1G/l6g+4DOSKbdJmUPdV2qDB6WX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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