SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2e77e5b3b8479cca6788d9a5969063127ad27c1f212d205cacce92e5077cadd' 
  AND token = 'imITVwUqaMcL3qUwQHTIu9H0h9+Jwcqp75M77emyUU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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