SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81651297eee546ce2a590629c2fddd228640d547958aa7456be07154ed5d5799' 
  AND token = 'Wooo82fxiaAMB7VTCNW5VC1RC7LSzEZqQecFRm9HH6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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