SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94263a1a151989e14b1548114c3e1c11cf7553f7f5829f161e19d73583d3268a' 
  AND token = 'RqCKL6sfDv/yp82k+OLn4X+CVBZpUPgjmjv5FWzVk5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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