SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad31e52c355bfa725a05e1caa9022308bd5167f9fd495fe89e2e588faceff3f' 
  AND token = 'JDjpk+xuT5WxtGQDolS+tXhMM7K1nnl3aarvGDgMIZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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