SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f27dacf618bdc71ee4ef170491ca3ae6c7cf3a138ababc35af831da9933a0cda' 
  AND token = '4qELJOYtvqWlmplDHfgWSuvqhuO0tqPukiFXcTl/UlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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