SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb76b051cbaa750a4c903854be96fde0b872758e2883caef9073ae60d87f277' 
  AND token = 'iJKCXxdcc9DljBY3dBWP+i1l+MPS0EBN6a1Lndnfx6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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