SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a7e5e410929f200f029d0a959604ff9263de08ae2fd59386474396624ddaa75' 
  AND token = 'FYd3cUqn0RXxBEwQ/vG+a7xcu4CMxlARvOT1UsGZKZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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