SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8795caf83ec5ee8ed10558bee5d2079fce5ead85e0863416f3f2e17dc84ede7' 
  AND token = 'QlJUe+Mu0YRiGjra9cAl8UqBIrBybjXYLr81BDXi1+c=' 
  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"
    }
  }
}