SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3dee89738e81877fca07f82046c02061d67aae07dbbd1c28e80d34b887f003c' 
  AND token = 'v5LOaX0NUolhOZIri/SSsAP1DSMVh4SeJode1QXEbIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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