SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd585acdce1a7c672fbb368c5469d724f50af169efed993510d035208afa89e44' 
  AND token = 'KTh9YIiPoCGr0dr3vt4c5XHI38xTH0n1FuZeLR34K5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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