SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5e0c484d9a37196e07afe867b486c612e12290cf3d84e0cd4b9603f37123134' 
  AND token = 'GQuLR8nC/WgqPMZZIS85fpMsv2h19G+A4hDZyWj4HbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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