SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542c7eaeae0a9f4b5737e6d8ecb6039b816ebb74e6ab054026263487aeccd0ce' 
  AND token = 'rdNBuqRMXLIu7MWiOaxgYTPpidXmKuloFCzbiYdWSiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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