SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be7f8d67298d981b48df5c2f8d13950d6dccbeb4664658fbed2a05c507ff0a64' 
  AND token = 'hL+nG2rVDIu7nE/aFk9WhYh4VLtoqTKaJI57Jcni+gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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