SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9214c42a18fdc950bc39de5e9ac23cd3b7f0abdfccd687bb7d9b4a7f2a29606' 
  AND token = 'TYpk4rrxS/nxwqZlZt+a4ww89BlBvMlbtGgOA0Gum+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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