SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7698af5125d268158b9c5dd44e241d579f3e2b0552ea51d1018ed6543c2c8969' 
  AND token = '5Rl4vq5QhTewrH8avZlw9T6/GWq9nwfpmHLabPH09Sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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