SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70f110d851a14d134cc2a21d5c9042c8776c84c6170e0217d705817b975c4d17' 
  AND token = 'P8+P/U67TF1a9T7IX7UukHYVxVtyGN30wff0OVItcAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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