SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a723c6cf8417ec1aa5d53904c8c2072a2cd4a65808f195b0e56278250d91288' 
  AND token = 'Lf5HsTKRREkHWOy9+B65LS98PwmVandWkXdn2RAnGVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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