SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896dd115ad2cceb82e31e317e523950e1a35267d4ef3545ee202532dc6836775' 
  AND token = 'hGVhLVnQfjQOPYk2O+3mULctRavmV8pdV8lymCCCKHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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