SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b72e9f1dbdc5872964add15922619279df2b174eecc7b637ead227e7ce9732c7' 
  AND token = 'bsIfq/NDBXWcZFDNwTJTbvy6ynBGSrEQQO0l1EV71nM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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