SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a800d93e6850525fb9095831fb4fd810309e67e705fd3641d3db375b082a53' 
  AND token = 'xMTOc+J+oDi0/CzKnNopxLDOHPTxOyPlOjuAjnweBlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}