SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e3439be00dff7455327bc65f645c2edaf97dfb0079b62d49cdc54064c478805' 
  AND token = 'y0t5YkaxQYoK79v/PRlduAnpU9WNv+2mETdfINTM2Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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