SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c815e0caecdf8a1737b069ec1b0152463ab0a274102cdf720dbb398c34f76121' 
  AND token = 'NYuoHOsYAP87U2EmiOjX/lfNK4lGz+DWr3jlLId9yv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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