SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5999a509d0f2d28df129117ff0b43cecff1535d62ab79d558ef3950992205fcb' 
  AND token = 'zIl1myDAO8CRcqscQUcUnm7IV9TVaCdyhwEoZ04yK1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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