SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9e665f883461f19319907c2a44f5c5e6d8b008a6e2a73c2250d257fd4c463e' 
  AND token = 'EyMUG6H+JTM8vNJ3Ph7nvAvwHglVNOo+gji00mU1HrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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