SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38afd4e2aedb52f206166d57cd77c5baff428310c4b361f73cf26df7708bab99' 
  AND token = 'WYZCUQvgQPUdpSfFBIdTWbCzAtxlnfB+C94x+crGDL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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