SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0a3785e810821bfceadd80c6f2279262a4ad9562b0fd07cf8ec4060f1d1801a' 
  AND token = 'Pdy02TZzK4scw9+p2DBD2fuvmIkQnFZWFcms85/UVoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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