SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f30b303b40d6d626eeabe29f90dcc4c2885c122c09ee242efb7e419cf73d89dd' 
  AND token = 'CYe2ka08KItz2tIFDxXPKUupxkqFbjG/UEqMk/SWIYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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